The invention relates to an apparatus for measuring and regulating the position of a wire end of a spiral spring in a coiling machine.
A machine for producing double-coned spiral springs having twisted ends for use in bed mattresses and sofa upholstery is disclosed in German Pat. No. 2,073,995. This machine is equipped with a step-advanced rotatable turret having several radially positioned gripping arms which transport the produced spiral springs from one stage of production to the next. At the first production station a spiral spring is coiled from a severed length of wire. At the following two stations both of the wire ends of the spring are twisted around their adjacent end coils to form closed circles.
Inconsistencies or non-uniformities in the lead wire characteristics result in dimensional fluctuations in the springs which are produced. Since the length of the wire is actually not affected by these inconsistencies, the primary effects are deviations in the position of the wire end of the wound spring. Deviations in the position of the wire end which are too great result in incorrect twists in the succeeding twisting operation, as performed by an apparatus of the type described in German Pat. No. 1,170,359.
Until now, a service person on the machine had to monitor the twising operation and make manual adjustments to the tool which determines the diameter of the spring coil, to thereby compensate for inconsistent deviations in the position of the wire end. In the case of poorer and hence cheaper qualities of wire, these adjustments required the major attention of the machine monitor, and were often barely able to be controlled. May disturbances were thus created which jeopardized economic production. Hence, the effectiveness of the machine was dependent on the competency of the operator and the quality of the wire.